Amount Of Copper Research Articles

Single atom Cu-N-C catalysts for the electro-reduction of CO2 to CO assessed by rotating ring-disc electrode

The electrochemical CO2 reduction reaction (CO2RR) to controllable chemicals is considered as a promising pathway to store intermittent renewable energy. Herein, a set of catalysts based on copper-nitrogen-doped carbon xerogel (Cu-N-C) are successfully developed varying the copper amount and the nature of the copper precursor, for the efficient CO2RR. The electrocatalytic performance of Cu-N-C materials is assessed by a rotating ring-disc electrode (RRDE), technique still rarely explored for CO2RR. For comparison, products are also characterized by online gas chromatography in a H-cell. The as-synthesized Cu-N-C catalysts are found to be active and highly CO selective at low overpotentials (from −0.6 to −0.8 V vs. RHE) in 0.1 M KHCO3, while H2 from the competitive water reduction appears at larger overpotentials (−0.9 V vs. RHE). The optimum copper acetate-derived catalyst containing Cu-N4 moieties exhibits a CO2-to-CO turnover frequency of 997 h−1 at −0.9 V vs. RHE with a H2/CO ratio of 1.8. These results demonstrate that RRDE configuration can be used as a feasible approach for identifying electrolysis products from CO2RR.

Liver Protection Effect of Red Rose Petal Methanol Extract in Copper-Induced Liver Injury in Male Wistar Rats

The human body requires low amounts of copper to maintain homeostasis, but high copper intake can cause various health problems. Many previous studies have been performed to look for natural products that can neutralize the excessive copper effect; one such natural product is a rose petal. Therefore, this study aims to investigate the liver protection effect of rose petals in copper-induced liver injury in male Wistar rats. This experimental study used thirty male Wistar rats that were grouped into five groups, including control, standard (quercetin), Rose Petal Methanol Extract-1 (400 mg/kg BW), 2 (800 mg/kg BW), and 3 (1,200 mg/kg BW). All groups were treated for 14 days, and all rats were given copper (II) sulfate suspension for the last three days. On the fifteenth day, all rats were sacrificed to obtain blood and liver tissue SGOT, SGPT, and liver histology study. The results showed that rose petal methanol extract significantly decreased SGOT and SGPT levels compared to the control group (P-value <0.05). The reduced area of ballooning degeneration and necrosis were in line with the increased dose of rose petal extract supported the liver protection effect of rose petal extract. Therefore, it can be concluded that rose petal methanol extract protects the liver against copper impacts.

Environmental conditions of the north-western Pacific ecosystems: trace element accumulation in Pacific salmon

The metals (Cu, Pb, Cd, Ni, Zn and Fe) in Pacific salmon were determined: Masu from the southeast Sakhalin Island coast, collected in 2017, Chum from the of Okhotsk and Japan Seas, collected in 2018-2019 in cages of salmon fish hatcheries and Sockey collected from two bays of the southeastern coast Kamchatka before entering the rivers, in 2021. It was established that the content of Zn, Ni, and Fe noticeably predominate in the organs and tissues of Cherry and Chum from the Sea of Japan, while Cd and Pb concentrations predominate in the organism of the Sea of Okhotsk Chum. The largest amount of copper was found in the organism of Sockey from Kamchatka bays. according to the content of toxic elements (Pb and Cd), all types of salmon meet the sanitary requirements of the Russia for seafood. Probably, the reason for the established difference is the geochemical environmental conditions formed in the closed Sea of Japan under the influence of anthropogenic and terrigenous factors, the influence of natural factors - volcanism and upwellings - in the Sakhalin-Kurilsky basin of the Sea of Okhotsk, also the increased background copper content in the Kamchatka soils because of volcanic activities.

Emeraldine Salt-Nanocarbon Composites as a Material for Copper Recovery from Industrial Wastewaters

Nanocarbon films are characterized by high surface area[1], appreciable electrical conductivity[2], and good mechanical properties[3]. These properties make them suitable for application as electrode materials in various electrochemical processes. For instance, nanocarbon electrodes can be used for selective deposition of metals onto their surface[4]. In particular, it is beneficial to accumulate Cu atoms on the surface of carbon nanomaterials as such composite exhibits much improved electrical conductivity and strength. To make this process as efficient as possible, functional groups containing oxygen or nitrogen are attached to the nanocarbon surface, prior to electrodeposition, but their presence may deteriorate the capabilities of material for charge propagation.Alternatively, conductive polymers such as polyaniline (PANI) can be physically attached to carbon to improve their electrochemical properties[5], without introducing defects in the structure that negatively affect the electrical properties of the material. Different forms of PANI have substantial effects on the properties of composites, emeraldine salts (ES) have been chosen based upon their higher electrical properties. ES are characterized by the highest increase in electrical and mechanical properties of composites.Our research focused on the selective deposition of metals onto ES-nanocarbon composites from industrial wastewaters, which contained such metals as magnesium, iron, nickel, and copper. Aniline was electropolymerized onto the nanocarbon surface by cyclic voltammetry to make the material more suitable for recovery of metals from such source. The process of copper recovery was highly selective, which was confirmed by characterization of the surface by EDX mapping. Despite the trace amounts of copper (428 ppm) in the used industrial wastewater, Cu nanoparticles were highly visible on the PANI-nanocarbon surface after just one hour of the process. Analogously, nickel has also been recovered by this method, which demonstrates that the presented approach may be tuned for deposition of various metals onto nanocarbon to make previously unreported nanocarbon-metal composites. P.S. would like to thank the Ministry of Education and Science (MEiN/2022/DIR/3086) of Poland for financial support, which enabled the attendance to the conference. G.S. and P.S. would like to thank the Ministry of Education and Science of Poland for financial support of scientific work from budget funds for science in the years 2019–2023 as a research project under the “Diamond Grant” program (grant agreement 0036/DIA/201948). G.S., P.S. and D.J. would like to thank the National Centre for Research and Development, Poland (under the Leader program, grant agreement LIDER/0001/L-8/16/NCBR/2017). P.S. acknowledges the National Agency for Academic Exchange of Poland (NAWA, (under the Academic International Partnerships program, grant agreement PPI/APM/2018/1/00004) for supporting training in the Aalto University, which enabled the execution of the study. GS would like to thank also NAWA (under the Iwanowska program, grant agreement PPN/IWA/2019/1/00017/UO/00001) for financial support during the stay at the University of Pittsburgh in the USA. M. Cadek et al, Nano Letters, 2004, 4, 2, 353–356G. Stando et al, Scientific Reports, 2022, 12, 4358J. Salvetat et al. Appl Phys A, 1999, 69, 255–260G. Stando et al, Water Resources and Industry, 2021, 26, 100156A. Kumar et al, Polymer-Plastics Technology and Engineering, 2018, 57, 2, 70-97

Changes during lactation in the mineral element content of mare milk produced in semi-extensive rural farms

This study characterizes, for the first time, the content of individual mineral elements in mare milk from Basque Mountain Horse breed, as well as changes that occur during lactation and among semi-extensive rural farms. Individual milk samples from eighteen mares belonging to three commercial farms were collected along six months of lactation, and the contents of eleven mineral elements in milk were determined using a triple quadrupole inductively coupled plasma mass spectrometer (ICP-MS). Basque Mountain Horse milk contained calcium (Ca; 958 ± 248 μg/g milk), potassium (K; 581 ± 117 μg/g milk), phosphorus (P; 454 ± 160 μg/g milk), sodium (Na; 141 ± 38 μg/g milk), magnesium (Mg; 64.1 ± 15.7 μg/g milk), zinc (Zn; 2.50 ± 0.88 μg/g milk) and copper (Cu; 0.343 ± 0.179 μg/g milk) amounts similar to those reported in other horse breeds. Conversely, low sulphur (S; 156 ± 42 μg/g milk) and chlorine (Cl; 49.3 ± 33.4 μg/g milk), and high iron (Fe; 2.43 ± 2.44 μg/g milk) contents were found. Mn was only quantifiable in 12% of the samples. The content of all macrominerals, except Na and Cl, decreased at the end of lactation, while that of trace elements (Zn, Cu and Fe) either increased or fluctuated. In addition, the content of Ca, P, S and Na differed significantly among semi-extensive rural farms, probably due to differences in feeding management. From a multivariate perspective, the mineral element composition of the milk made it possible to differentiate samples from early, mid and late lactation stage.

Co-exposure to Fe, Zn, and Cu induced neuronal ferroptosis with associated lipid metabolism disorder via the ERK/cPLA2/AA pathway

Excessive amounts of iron (Fe), zinc (Zn), and copper (Cu) can be toxic to neuronal cells, even though these are essential trace elements for animals and humans. However, the precise mechanisms underlying the neurotoxicity of exposure to mixtures of Fe, Zn, and Cu are still mostly unclear. The research aimed to investigate the influence of co-exposure to iron, zinc and copper and the related mechanisms in HT22 murine hippocampal neuronal cells. Intracellular metal content, markers of oxidative damage, and biomarkers of ferroptosis were respectively detected. Afterward, metabolomic analyses were performed to obtain a comprehensive understanding of the metal mixtures on metabolism, and the functions of key enzymes on metabolic pathways were validated. The results showed that metal co-exposure resulted in cellular iron overload and increased lipid peroxidation, accompanied by significant pathological damage and mitochondrial abnormalities in HT22 cells. Meanwhile, it was found that GSH depletion, decreased GPX4, and increased expression of the lipid metabolism gene ACSL4 play important roles in ferroptosis induced by metal mixture. Further, metabolomic analysis revealed metal co-exposure induced significant alterations in metabolite levels, especially in the glycerophospholipid metabolism pathway and the arachidonic acid metabolism pathway. The levels of cPLA2 and its metabolite, arachidonic acid, were significantly increased after metal co-exposure. Then, inhibition of cPLA2 decreased the level of arachidonic acid and attenuated ferroptosis in neuronal cells. Collectively, our findings unveiled ferroptosis induced by metal co-exposure associated with crucial molecular changes in neuronal cells, providing a novel perspective on the comprehensive toxicity risk assessment of metal mixtures.

Nutritional Composition of House Cricket (Acheta domesticus) and Dung Beetle Larva (Oryctes boas) in Osun State: Implication to Dietary Improvement in Nigeria

Background: Edible insects and the act of eating insects (Entomophagy) are common across the globe. Feeding variations and species differences, among other factors, influence these individuals’ chemical and mineral components. The current study elucidated the nutritional composition of house cricket (Acheta do-mesticus) and dung beetle larva (Oryctes boas) collected in Osun State, Southwestern Nigeria. Methods: The nutritional composition of the two species of insects sampled randomly was determined following standard methods of the Association of Official Analytical Chemists. The ground crickets and beetle larvae were digested with HNO3 and HCl in a microwave digestion system; inductively coupled plasma-optical emission was used to determine the amounts of Calcium, Sodium, Potassium, Phosphorus, Magnesium, Iron, Copper, Manganese, and Zinc in the samples. Following a standard procedure, the amino acid profile was performed using a Biochrom30+ amino acid analyzer (Pharmacia-Biotech, Buckinghamshire, UK). Data obtained were expressed as means ± standard deviations of triplicate analyses and compared among the two insect species using Student’s t-test at p < 0.05. Results: Generally, the nutritional components of A. domesticus were higher than that of O. boas. The O. boas was not significantly higher (P> 0.05) in Iron (6. 83 ± 1. 80 mg/100 g dry matter) but significantly high-er (P< 0.05) in Magnesium (730. 94 ± 2. 64 mg/100 g dry matter) than A. domesticus. All Essential Amino Acids (EAAs) and Non-Essential Amino Acids (NEAAs) were present in the two insect species with varying concentrations. House cricket, however, has a significantly higher (P< 0.05) Arginine, Valine, Phenylalanine, Glutamine, and Glutamic Acid than O. boas. Conclusion: The two insects under this study are edible and of great nutritional values. The results of the nutritional composition of Acheta domesticus and Oryctes boas may serve as the basis for improvement in human food and feed formulation in Nigeria

Copper–zinc/chitosan complex hydrogels: Rheological, degradation and biological properties

Polymer hydrogels crosslinked by therapeutic metal ions have attracted increased interest in recent years due to their unique and versatile properties. Chitosan hydrogels are widely investigated for various biomedical applications such as tissue engineering and drug delivery. Copper and zinc ions are considered as therapeutic metal ions, that have important roles in bone regeneration. The aim of this study was to investigate the physicochemical and biological properties of bimetallic–chitosan complex hydrogels with different cupric and zinc ions content. Scanning electron microscopy (SEM) revealed changes in the morphology from the microstructure with larger, tubular pores for aerogels with higher Zn content, to the sheets-like structure with long pores for samples with higher Cu content. FTIR analysis indicated the formation of bimetallic–chitosan aerogels. The obtained X-ray diffraction patterns showed a broadening of chitosan's characteristic diffraction maximum, while characterization of physical properties showed decreased swelling ability and increased shear modulus with higher Cu content. ICP-MS results showed a negligible amount of copper and zinc ions released under physiological conditions during 24 h indicating a strong physical crosslink between metal ions and chitosan chains. Furthermore, accelerated in vitro degradation showed that hydrogels maintained good stability during four weeks of lysozyme activity. The MTT assay indicated that the cytotoxicity of Cu2+–Zn2+/chitosan complexes could be adjusted by the amount of cupric ions. All results imply that Cu2+ and Zn2+ ions act as physical crosslinkers of the polymer network. Also, results are in agreement with the prediction of density functional theory (DFT) which indicated stronger chitosan–Cu tetrahedral aqua complex interactions in comparison to the chitosan–[Zn(H2O)4]2+ interactions.

Assessment of Nutrient Levels Provided by General Hospital Patient Menus: A Cross-Sectional Study Carried Out in the Region of Murcia (Spain).

Disease-related malnutrition remains a health problem with a high prevalence that increases the risk of poor patient outcomes, in addition to an elevation of healthcare costs. The aim of this study was to evaluate the nutritional quality of the menus at Ribera Molina Hospital, including their adequacy regarding recommended daily nutrient intakes and the agreement with the theoretical nutrition information provided by catering. The mean levels of energy, macronutrients, vitamins, and minerals provided by the basal, diabetic, and soft diets were calculated through the weighing of plated food served throughout the first 14 days of February 2020. A nutritional overestimation was seen in the nutrition information provided by the catering compared to the values derived from weighing foods (p < 0.01). Despite this, the nutritional content calculated by weighing satisfied the energy and protein requirements of 203 hospitalized patients previously studied in the internal medicine area of the hospital. The mean age of these patients was 62 years, and the main causes of admission were lung, cardiovascular, renal, and digestive diseases. There seems to be an insufficient amount of vitamins E and D, as well as magnesium, on all the menus. A possible insufficient amount of calcium, potassium, zinc, and copper was observed in some of the menus studied. It is necessary to update the hospital prescription manual so the nutritional contents of the diets are accurate and based on the weighted and calculated values to improve the adequacy of diets prescribed to patients.

Copper-bearing titanium alloy prepared by two-wire electron beam additive manufacturing with enhanced antibacterial activity

Bacterial biofilms on titanium implant surfaces may lead to the development of peri-implant diseases. For the first time, Ti6Al4V/Cu prepared by double-wire electron beam additive manufacturing (EBAM) were subjected to in-vitro antimicrobial test. The antimicrobial activity of the materials was investigated against S.aureus and C.albicans strains depending upon the amount of copper added. Increasing the copper content in material to 9.7 wt% allowed achieving 99% bacterial population reduction on the copper-containing substrate. Such an enhanced antimicrobial acivity of the substrate was caused by the release of copper ions from the Ti6Al4/Cu alloys.

Preliminary verification of the MCNP perturbation and fixed-source tally sensitivity tools

Integral benchmark experiments are vital in the adjustment and validation of the nuclear data that govern predictive simulations across the nuclear community. The nuclear data sensitivity capabilities of the Monte Carlo N-Particle (MCNP ®) transport code are currently limited; however, expanding sensitivity capabilities will allow benchmark experiments to be designed to resolve compensating errors and adjust nuclear data where previously prohibitively difficult. This paper provides details of a preliminary verification for the use of (i.) the recently revised perturbation and (ii.) developmental fixed-source sensitivity tools within MCNP to calculate sensitivities of tallied responses (such as current integrated over a surface, F1, and flux averaged over a cell, F4) to nuclear data in fixed-source simulations. Energy-binned and energy-integrated sensitivities calculated with these tools are compared against sensitivities calculated using a central-difference approximation. The verification is completed for four configurations of a benchmarked system using a 4.5-kg plutonium sphere surrounded by varying amounts of copper and/or polyethylene. The results show that sensitivities calculated with the perturbation and fixed-source sensitivity tools agree with the central-difference-based approach.

Mineralogy of Agates with Amethyst from the Tevinskoye Deposit (Northern Kamchatka, Russia)

The Tevinskoye agate deposit is located in the North of the Kamchatka peninsula (Russia) and represented by agate-bearing Eocene basaltic and andesitic rocks of the Kinkilsk complex. Agate mineralization occurs in lavas and tuffs as amygdales, geodes, lenses and veins, which are the main sources of the resupply of coastal agate placers. The present study aimed to perform a comprehensive mineralogical, geochemical, and O-isotope investigation of amethyst-bearing agates, and to evaluate data concerning the origin of mineralization and the conditions for amethyst formation. Agates exhibit spectacular textures, with variation in the sequence of silica filling of amygdales and geodes. The mineral composition of the agates is mainly represented by micro- and macro-crystalline quartz, amethyst, length-fast and zebraic chalcedony, moganite, goethite, and clinoptilolite. Carbonate forms individual bands in the outer zones of some agates. The presence of small amounts of native copper, covellite, chalcopyrite and pyrite is a feature of these agates. Copper and iron mineralization are probably typomorphic features related to the host rock composition. The measured values of crystallite size (525–560 Å) and the high moganite content (up to 50%) of agate with amethyst are evidenced by the young age (~45 Ma) of agate-hosting rocks. Agate formation temperatures (21–229 °C) were calculated from the O-isotope composition of chalcedony (+19.6 to +25.5‰), quartz (+18.1 to +22.3‰), and amethyst (+18.2 to +21.5‰). The cold-water monophase fluid inclusions revealed in amethyst crystals suggest that the mineralizing fluids have low temperatures (&lt;100 °C) and low salinity. Magnetite grains in host rock, together with goethite inclusions identified within the amethyst crystals, point to a change in redox conditions and the presence of iron in the agate-forming fluids, which entered the quartz lattice during crystallization and influenced the formation of the violet color.

The effect of Cu ions concentration on electrochromic properties of Cu embedded PANI thin films

In this paper, copper salt (CuSO4.5H2O) has been used to improve electro-optical performances of PANI electrochromic layers including color switching rate (from transparent to colored state) and stability. For this purpose, the PANI solution was chemically prepared in the presence of different amounts (0.018, 0.03, 0.25, 0.5 and 2.5%w) of copper ions concentration by electrodeposition technique on a fluorine doped tin oxide (FTO) glass, which was used as a transparent conductive electrode and substrate. Finally, the five PANI/Cu samples were characterized and compared with pure PANI electrochromic layer. As a result, with cyclic voltammetry analysis and photospectroscopy, in the most optimal amount of copper (0.03%w) the optical contrast of the Cu embedded PANI electrochromic layer enhanced from 15% to 52.5%, its coloring time improved from 3 s to 1.3 s and its stability was the best.

Effects of aging heat treatment on microstructure and corrosion behavior of friction surfacing treated Al–Zn–Mg–Cu matrix composite

The effect of artificial aging heat treatment on the microstructure and corrosion behavior of Al–Zn–Mg–Cu matrix composite was studied. Nickel-aluminide reinforcement was fabricated in-situ during the stir casting process of Al–Zn–Mg–Cu alloy. After friction surfacing of the consumable rod of an as-cast composite on AA1050 substrate and post-processing artificial aging heat treatment at 125 °C for 18 h, significant grain growth was observed in the nickel-free sample. Moreover, the presence of nickel-aluminide reinforcement in the microstructure of composite resulted in the formation of bimodal microstructure. The presence of nickel-rich particles and the strengthening mechanism through precipitates could help increase the hardness and strength in the nickel-containing sample. After artificial aging heat treatment, the shear strength and hardness of composite containing nickel-aluminide increased by 24% and 13%, respectively, more than those of the aluminum matrix. Before aging heat treatment, the pitting corrosion resistance was significantly improved by the presence of nickel-containing particles. After aging heat treatment due to the adsorption of more significant amount of soluble copper by nickel-rich particles in the nickel-containing sample, corrosion resistance decreased by 39% compared to that of the nickel-free sample.

Hydrothermal Fabrication of Carbon-Supported Oxide-Derived Copper Heterostructures: A Robust Catalyst System for Enhanced Electro-Reduction of CO2 to C2 H4.

Anthropogenic CO2 can be converted to alternative fuels and value-added products by electrocatalytic routes. Copper-based catalysts are found to be the star materials for obtaining longer-chain carbon compounds beyond 2e- products. Herein, we report a facile hydrothermal fabrication of a highly robust electrocatalyst: in-situ grown heterostructures of plate-like CuO-Cu2 O on carbon black. Simultaneous synthesis of copper-carbon catalysts with varied amounts of copper was conducted to determine the optimum blend. It is observed that the optimum ratio and structure have aided in achieving the state of art faradaic efficiency for ethylene >45 % at -1.6 V vs. RHE at industrially relevant high current densities over 160 to 200 mA ⋅ cm-2 . It is understood that the in-situ modification of CuO to Cu2 O during the electrolysis is the driving force for the highly selective conversion of CO2 to ethylene through the *CO intermediates at the onset potentials followed by C-C coupling. The excellent distribution of Cu-based platelets on the carbon structure enables rapid electron transfer and enhanced catalytic efficiency. It is inferred that choosing the right composition of the catalyst by tuning the catalyst layer over the gas diffusion electrode can substantially affect the product selectivity and promote reaching the potential industrial scale.

The Effect of Heat Treatment for Alloys (Aluminum - Copper) on some Mechanical Properties

In this work, the preparation and processing of aluminum-copper alloys, which added amounts of copper to aluminum in different parentages (2, 4, 5%) so that it does not exceed the saturation limit for aluminum (6% Copper). After adding these specific amounts of copper to aluminum, have been melting each alloy to thaw copper in aluminum fully and diffusion copper atoms in it, and after that the specimens were prepared and quenched at 8-30 hours and rapid cooling in the water, and then were studied parameters of heat treatment and different percentages of copper. It is clear from the schemes and experimental results that each weight ratio of copper in aluminum has a different approach to reach the best mechanical properties. After performing mechanical tests and tests, it was found that the highest hardness of the (aluminum-copper) alloy in the case of (2% Cu) amounted to (120 HB) and in the case of (4% Cu) the amount (211 HB) and in the case of (5% Cu) the amount (188 HB).

RECOVERY OF PHENOL-FORMALDEHYDE SOLID WASTE FROM THE PRODUCTION OF INORGANIC THERMAL INSULATING MATERIALS

The production of inorganic thermal insulation materials with a fibrous structure, consisting of a fibrous skeleton and air pores, generates phenol-formaldehyde solid waste. Formaldehyde resin is used to crosslink, or glue, fibers together, so that most of the phenol and formaldehyde released after evaporation is found in wastewater, while the remaining part is generated as solid waste. The paper characterizes solid waste using the following chemical analyses: UV-VIS spectrophotometry, atomic absorption spectrophotometry, and gas chromatography. This is done with the aim to provide a more detailed consideration of the pollution potential. Based on the conducted research, it can be concluded that the drainage water according to the criteria for underground water contains increased amounts of copper, cadmium, lead, chromium, cobalt, nickel and phenol. At the same time, the concentrations of copper, cadmium, nickel and phenol also exceed the values, which is a condition that requires more detailed investigations. The concentration of phenol is getting close to the threshold value (0.050 mg/dm3), according to which measures are recommended. The paper proposes an eco-technical solution for waste stabilization through supercritical aqueous oxidation of phenol-formaldehyde and metal waste.

Copper-manganese oxide catalysts prepared by solution combustion synthesis for total oxidation of VOCs

A set of Cu-Mn oxides was prepared through the simple and effective solution combustion synthesis method by varying the relative amount of copper and manganese. The physico-chemical properties of the samples were investigated through complementary techniques such as N2 physisorption at − 196 °C, XRD, HR-TEM, Raman spectroscopy, temperature programmed analyses (H2-TPR, O2-TPD, and NH3-TPD), and XPS. The prepared catalysts were tested for the total oxidation of volatile organic compounds (ethylene, propylene, and toluene). The best performances, in terms of total VOC oxidation, were achieved with a copper content ranging from 15 at% to 45 at%. The catalytic test outcomes demonstrate the beneficial effect of acidic sites, oxygen mobility, and redox ability. In particular, ethylene oxidation is mainly favored by oxygen vacancies and redox properties, while propylene and toluene oxidation is mostly enhanced by acidic sites. All the catalysts prepared can totally oxidize the examined pollutants examined below 310 °C. Moreover, the binary oxides exhibit good catalytic stability over a time-on-stream of 7 h and low water vapor inhibition (5 vol% H2O in the gas stream).

Key factors determining the bulk ore sorting potential in a caving mine

Bulk ore sorting may add significant value to block and panel cave mines where processing feed grades are constrained by limited grade selectivity. The Cadia East gold-copper mine is a panel caving operation utilizing two different on-belt bulk ore sensors to evaluate the potential benefits of the technology. To date, there is limited reported work addressing the applicability of bulk ore sorting systems at a caving mine, where two commodities drive the economics. This indicative study is aimed at investigating the importance of various key factors on the bulk ore sorting potentials of the active and future panel caves of the Cadia East mine. Results show that for only one active cave of the mine, bulk ore sorting may be applied in the ideal scenario where grades are not affected negatively by mixing and the sorting takes place at maximum efficiency. As a general trend for all the caves, when the sorting cut-off grade is increased beyond a certain threshold, a sharp decline is observed in the sorting potentials due to the significant amounts of gold and copper deporting to the sorter rejects. In the case of a significant drop in metal prices, bulk ore sorting may only provide an opportunity to improve cave economics marginally. Results obtained by investigating the spatial change in sorting potential show that the portions of the caves with low metal grades are favourable for bulk ore sorting. In the scenario where bulk ore sorting is focused on low-grade portions, it is demonstrated that improvements in the economics of the future caves may additionally be achieved. However, as the low-grade portions represent a very small volume in the orebody, applying ore sorting on the plant conveyor may not be viable.

Inhibition of nitrous oxide reduction in forest soil microcosms by different forms of methanobactin.

Copper plays a critical role in controlling greenhouse gas emissions as it is a key component of the particulate methane monooxygenase and nitrous oxide reductase. Some methanotrophs excrete methanobactin (MB) that has an extremely high copper affinity. As a result, MB may limit the ability of other microbes to gather copper, thereby decreasing their activity as well as impacting microbial community composition. Here, we show using forest soil microcosms that multiple forms of MB; MB from Methylosinus trichosporium OB3b (MB-OB3b) and MB from Methylocystis sp. strain SB2 (MB-SB2) increased nitrous oxide (N2 O) production as well caused significant shifts in microbial community composition. Such effects, however, were mediated by the amount of copper in the soils, with low-copper soil microcosms showing the strongest response to MB. Furthermore, MB-SB2 had a stronger effect, likely due to its higher affinity for copper. The presence of either form of MB also inhibited nitrite reduction and generally increased the presence of genes encoding for the iron-containing nitrite reductase (nirS) over the copper-dependent nitrite reductase (nirK). These data indicate the methanotrophic-mediated production of MB can significantly impact multiple steps of denitrification, as well as have broad effects on microbial community composition of forest soils.